<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<select id="sty" onchange="change()">
			<option value=1>样式1</option>
			<option value=2>样式2</option>
			<option value=3>样式3</option>
		</select>
		
		<h1>你好你好你好你好你好你好<br>
		你好你好你好你好你好你好<br>
		你好你好你好你好你好你好<br></h1>
		
		<script type="text/javascript">
			function change()
			{
				switch(sty.value){
					case "1":
					document.body.style.background="#000000"
					document.body.style.color="#fff"
					break
					case "2":
					document.body.style.background="#6cf"
					document.body.style.color="#888"
					break
					case "3":
					document.body.style.background="#79cc77"
					document.body.style.color="#f00"
					break
					
				}
				
			}
			
		</script>
		
	</body>
</html>
